Constitutive models for microvoid nucleation, growth and coalescence in elastoplasticity, finite element reference modelling

1995 ◽  
pp. 107-122 ◽  
Author(s):  
J. Oudin ◽  
B. Bennani ◽  
P. Picart
Keyword(s):  
Finite Element ◽  
Constitutive Models ◽  
Nucleation Growth

Analytical and Numerical Predictions of Thermoelastic Properties of Carbon Single-Walled Nanotubes

Aerospace ◽  
2005 ◽  
Author(s):  
Vinod P. Veedu ◽  
Davood Askari ◽  
Mehrdad N. Ghasemi-Nejhad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Graphene Sheet ◽  
Effective Properties ◽  
Constitutive Models ◽  
Thermoelastic Properties ◽  
Asymptotic Homogenization ◽  
Element Analysis ◽  
Single Walled Nanotubes ◽  
Numerical Predictions

The objective of this paper is to develop constitutive models to predict thermoelastic properties of carbon single-walled nanotubes using analytical, asymptotic homogenization, and numerical, finite element analysis, methods. In our approach, the graphene sheet is considered as a non-homogeneous network shell layer which has zero material properties in the regions of perforation and whose effective properties are estimated from the solution of the appropriate local problems set on the unit cell of the layer. Our goal is to derive working formulas for the entire complex of the thermoelastic properties of the periodic network. The effective thermoelastic properties of carbon nanotubes were predicted using asymptotic homogenization method. Moreover, in order to verify the results of analytical predictions, a detailed finite element analysis is followed to investigate the thermoelastic response of the unit cells and the entire graphene sheet network.

Three-Dimensional Finite Element Modeling of Drilling Processes

2006 ◽  
Author(s):  
T. D. Marusich ◽  
S. Usui ◽  
R. Aphale ◽  
N. Saini ◽  
R. Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Simulation Software ◽  
Process Conditions ◽  
Third Wave ◽  
Element Modeling ◽  
Drill Point ◽  
Three Dimensional Finite Element

The three dimensional (3D) finite element modeling (FEM) and experimental validation of drilling are presented. The Third Wave AdvantEdge machining simulation software is applied for the FEM. It includes fully adaptive unstructured mesh generation, thermo-mechanically coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, and constitutive models appropriate for process conditions and finite deformation analyses. The workpiece is modeled with a predrilled cone-shape blind hole to enable the early full-engagement of the whole drill point region to reduce the simulation time. Drilling experiments are conducted on the Ti-6Al-4V using a twist drill geometry. The calculated cutting force and torque are compared with the results of experiments with good agreement. Effects of process parameters on the stress and temperature distributions of the drill and workpiece are investigated in detail using the FEM.

Investigations of PMN-PT Single Crystal Performance

2010 ◽  
Author(s):  
Virginia G. DeGiorgi ◽  
E. P. Gorzkowski ◽  
M.-J. Pan ◽  
M. A. Qidwai ◽  
Stephanie A. Wimmer
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Single Crystals ◽  
Domain Switching ◽  
Fatigue Behavior ◽  
Constitutive Models ◽  
Nonlinear Behavior ◽  
Computational Effort ◽  
Basic Material ◽  
Poling Direction

Application of new materials, such as PMN-PT single crystals, requires a good understanding of basic material performance under both electrical and mechanical loading. Over the past 5 years the authors have used both computational and experimental techniques to examine the relationships between poling direction, crystal orientation, and electric field actuation. Experiments show mixed results indicating that the relationship between material orientation and loading is more complex than originally imagined. In some cases crack initiation and propagation perpendicular to the applied field was observed within a few thousand cycles but in other cases no failure was observed even after a few hundred thousand cycles despite crack growth in the presence of introduced defects. Computational effort quickly identified a gap between development of theoretical constitutive models that addressed domain switching based nonlinear behavior and what was available in workable form as part of commercial finite element codes. This led to the implementation of a macro-mechanical constitutive model which addresses domain switching, into a commercially available finite element code. The rate independent version has been used to investigate issues of electric field actuation and poling direction. Presented here are insights into the fracture and fatigue behavior of piezoelectric single crystals from both experimental and computational studies.

scholarly journals Finite element modelling of an energy-geomembrane underground pumped hydroelectric energy storage system

2020 ◽  
Vol 205 ◽  
pp. 07001
Author(s):  
Hans Henning Stutz ◽  
Peter Norlyk ◽  
Kenneth Sørensen ◽  
Lars Vabbersgaard Andersen ◽  
Kenny Kataoka Sørensen ◽  
...  
Keyword(s):  
Finite Element ◽  
Energy Storage ◽  
Storage System ◽  
Constitutive Models ◽  
Energy System ◽  
Energy Storage System ◽  
Elastic Model ◽  
Hydroelectric Energy ◽  
Linear Elastic ◽  
Soil Behaviour

The increasing need for energy storage technology has led to a massive interest in novel energy storage methods. The energy geomembrane system is such a novel energy storage method. The concept of the system is briefly introduced, and a holistic numerical model of the system is presented. The model uses advanced finite-element techniques to model the energy storage system using fluid cavity elements. The developed geomembrane energy system is modelled with different constitutive models to represent the soil behaviour: a linear elastic model, a nonlinear Mohr-Coulomb model, and a hypoplastic constitutive model. The consequences of these different models on the results are studied. Hereby, the focus is the first inflation and deflation cycle of the system.

scholarly journals Application of the Generalized Nonlinear Constitutive Law in 2D Shear Flexible Beam Structures

2021 ◽  
Author(s):  
Damian Mrówczyński ◽  
Tomasz Gajewski ◽  
Tomasz Garbowski
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Reference Model ◽  
Constitutive Models ◽  
Constitutive Law ◽  
Flexible Beam ◽  
Beam Model ◽  
Beam Structures ◽  
Nodal Displacements ◽  
Nonlinear Constitutive Law

The paper presents a modified finite element method for nonlinear analysis of 2D beam structures. To take into account the influence of the shear flexibility, a Timoshenko beam element was adopted. The algorithm proposed enables using complex material laws without the need of implementing advanced constitutive models in finite element routines. The method is easy to implement in commonly available CAE software for linear analysis of beam structures. It allows to extend the functionality of these programs with material nonlinearities. By using the structure deformations, computed from the nodal displacements, and the presented here generalized nonlinear constitutive law, it is possible to iteratively reduce the bending, tensile and shear stiffnesses of the structures. By applying a beam model with a multi layered cross-section and generalized stresses and strains to obtain a representative constitutive law, it is easy to model not only the complex multi-material cross-sections, but also the advanced nonlinear constitutive laws (e.g. material softening in tension). The proposed method was implemented in the MATLAB environment, its performance was shown on the several numerical examples. The cross-sections such us a steel I-beam and a steel I-beam with a concrete encasement for different slenderness ratios were considered here. To verify the accuracy of the computations, all results are compared with the ones received from a commercial CAE software. The comparison reveals a good correlation between the reference model and the method proposed.

Finite Element Analysis of Hyperelastic Components

1998 ◽  
Vol 51 (5) ◽  
pp. 303-320 ◽  
Author(s):  
D. W. Nicholson ◽  
N. W. Nelson ◽  
B. Lin ◽  
A. Farinella
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Recent Literature ◽  
Constitutive Models ◽  
Review Article ◽  
Considerable Extent ◽  
Arc Length ◽  
Numerical Techniques ◽  
Element Analysis ◽  
Current Review

Finite element analysis of hyperelastic components poses severe obstacles owing to features such as large deformation and near-incompressibility. In recent years, outstanding issues have, to a considerable extent, been addressed in the form of the hyperelastic element available in commercial finite element codes. The current review article, which updates and expands a 1990 article in Rubber Reviews, is intended to serve as a brief exposition and selective survey of the recent literature. Published simulations are listed. Rubber constitutive models and the measurement of their parameters are addressed. The underlying incremental variational formulation is sketched for thermomechanical response of compressible, incompressible and near-incompressible elastomers. Coupled thermomechanical effects and broad classes of boundary conditions, such as variable contact, are encompassed. Attention is given to advanced numerical techniques such as arc length methods. Remaining needs are assessed. This review article contains 142 references.

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